Ungku Ferwani Salwa Ungku Ibrahim

Bio: Ungku Ferwani Salwa Ungku Ibrahim is an academic researcher from University of Malaya. The author has contributed to research in topics: Radio astronomy & Dwarf galaxy. The author has an hindex of 5, co-authored 10 publications receiving 103 citations. Previous affiliations of Ungku Ferwani Salwa Ungku Ibrahim include Universiti Teknologi MARA.

Intelligent Control for Self-erecting Inverted Pendulum Via Adaptive Neuro-fuzzy Inference System

Abstract: A self-erecting single inverted pendulum (SESIP) is one of typical nonlinear systems. The control scheme running the SESIP consists of two main control loops. Namely, these control loops are swing-up controller and stabilization controller. A swing-up controller of an inverted pendulum system must actuate the pendulum from the stable position. While a stabilization controller must stand the pendulum in the unstable position. To deal with this system, a lot of control techniques have been used on the basis of linearized or nonlinear model. In real-time implementation, a real inverted pendulum system has state constraints and limited amplitude of input. These problems make it difficult to design a swing-up and a stabilization controller. In this paper, first, the mathematical models of cart and single inverted pendulum system are presented. Then, the Position-Velocity controller is designed to swing-up the pendulum considering physical behavior. For stabilizing the inverted pendulum, a Takagi-Sugeno fuzzy controller with Adaptive Neuro-Fuzzy Inference System (ANFIS) architecture is used to guarantee stability at unstable equilibrium position. Experimental results are given to show the effectiveness of these controllers.

Preliminary analysis of investigation Radio Frequency Interference (RFI) profile analysis at Universiti Teknologi MARA

Abstract: In this paper, we have identified some important Radio Frequency Interference (RFI) sources that can potentially be a problem for any future radio astronomical observations in Universiti Teknologi MARA (UiTM) and possibly in Malaysia as a whole. Analysis is done by classifying and characterizing the strength of the sources' RFI profiles. Comparison of the RFI profiles between the indoor (Faculty of Applied Sciences) and outdoor (Square Parade) areas are also presented. Some suggestions in improving the quality of radio frequency profile are recommended.

Radio Astronomy in Malaysia: Current Status and Outreach Activities

Abstract: In this paper, we will present the current status of radio astronomical research and outreach in Malaysia. We will also present a short history of our research group, which is currently the only radio astronomical facility in Malaysia. Our group is called the Radio Cosmology Research Lab and was established in 2005 by Dr Zamri Zainal Abidin and Prof Dr Zainol Abidin Ibrahim. We will discuss the future plans for this group including our keen interest in being part of a more global network of radio astronomers. We are already an active member of the South-East Asia Astronomy Network (SEAAN) and aims to have a radio astronomical facility in order to join the Global Very Long Baseline Interferometer (VLBI) as well becoming a research hub for the future Square Kilometer Array (SKA) project. We will also present some of the scientific goals of our group including providing a platform for radio astronomers to be able to do observations of weak and high red-shifted radio objects such as galaxy clusters and supernovae.

The Study of Radio Frequency Interference (RFI) in Altitude Effect on Radio Astronomy In Malaysia And Thailand

Abstract: 8 Abstract: Radio astronomy uses the radio spectrum to identify weak emissions from outer space sources and the others signal so-called Radio Frequency Interference (RFI). It is a very important issue to address in order to setup a radio astronomical facility. Different altitude of observation for example will effect on RFI level or noise environment to radio astronomy. In this paper, we report the initial testing of the usage of this system in order to classify the areas with the lowest RFI. The important parameter used to develop the database for our modeling is information on elevation or altitude. Three selected sites were Doi Inthanon National Park (Chiang Mai site), Pha Taem National Park, Ubon Ratchatani (Ubon site) and University of Malaya (UM site). University of Malaya site was use as a reference site. The RFI surveys are done to study Hydrogen lines (1400-1427MHz). The spectra RFI in these windows was carefully measured and monitored. In this paper, we report the initial testing of the usage of this system in order to classify the areas with the lowest RFI. The measured averaged RFI floor noise levels for Ubon, Chiang Mai and UM sites are -97.4291 (±2.17) dBm, -96.6217 (±4.05) dBm, - 97.0157 (±2.66) dBm for the narrow band (1300-1500MHz) and -97.5295 (±4.54) dBm, -93.5205 (±6.87) dBm, - 97.9551(±5.03) for wide band (1MHz-2800MHz). Our target is to locate the best location for the purpose of building a radio astronomical dish system in Thailand. In this paper, we will also discuss the possibilities of the planned science goals that can be done with the future radio telescope facility in Thailand.

The study of radio frequency interference (RFI) in altitude effect on radio astronomy in Malaysia and Thailand

Abstract: 8 Abstract: Radio astronomy uses the radio spectrum to identify weak emissions from outer space sources and the others signal so-called Radio Frequency Interference (RFI). It is a very important issue to address in order to setup a radio astronomical facility. Different altitude of observation for example will effect on RFI level or noise environment to radio astronomy. In this paper, we report the initial testing of the usage of this system in order to classify the areas with the lowest RFI. The important parameter used to develop the database for our modeling is information on elevation or altitude. Three selected sites were Doi Inthanon National Park (Chiang Mai site), Pha Taem National Park, Ubon Ratchatani (Ubon site) and University of Malaya (UM site). University of Malaya site was use as a reference site. The RFI surveys are done to study Hydrogen lines (1400-1427MHz). The spectra RFI in these windows was carefully measured and monitored. In this paper, we report the initial testing of the usage of this system in order to classify the areas with the lowest RFI. The measured averaged RFI floor noise levels for Ubon, Chiang Mai and UM sites are -97.4291 (±2.17) dBm, -96.6217 (±4.05) dBm, - 97.0157 (±2.66) dBm for the narrow band (1300-1500MHz) and -97.5295 (±4.54) dBm, -93.5205 (±6.87) dBm, - 97.9551(±5.03) for wide band (1MHz-2800MHz). Our target is to locate the best location for the purpose of building a radio astronomical dish system in Thailand. In this paper, we will also discuss the possibilities of the planned science goals that can be done with the future radio telescope facility in Thailand.

Identification and Control of Nonlinear Systems using Soft Computing Techniques

Abstract: The inverted pendulum is a highly nonlinear and open-loop unstable system. This means that standard linear techniques cannot model the nonlinear dynamics of the system, Inverted pendulum system is often used as a benchmark for verifying the performance and effectiveness of a new control method because of the simplicities of the structure. In this paper an accurate model of the inverted pendulum system, a neural network controller and ANFIS (Adaptive Neuro-Fuzzy Inference System) controller to stabilize the system have been developed. A control law that removes some of the nonlinearities from the process and allows the process to exhibit its dynamics has been developed. This aids in stabilizing the nonlinear pendulum. The quality of the data input has also been improved, since only limited number of variables that can be measured accurately are included in the system identification Simulation results establishes that the proposed controller has good set point tracking and disturbance rejection properties.

Dynamic modeling and control of a two wheeled robotic vehicle with a virtual payload

Abstract: One of the challenging issues to consider in balancing a two-wheeled robotic machine (TWRM) is when the load carried by the machine is changing position along the vehicle intermediate body (IB). An issue of interest in this case is the resulting impact on the system behaviour due to changing position of the load. Further complications arise with changing the size of the load. This work presents investigations into controlling a TWRM with a payload positioned at different locations along its IB. Two types of control techniques are developed and implemented on the system, the traditional proportional-derivative (PD) control and fuzzy logic (FL) control. PD and PD-fuzzy logic control techniques are developed to balance the vehicle with a payload incorporating two different scenarios. Firstly, the payload is positioned at different locations along its IB. Secondly, it is considered to perform a continuous sliding motion along the IB. The balancing of the robot has to be achieved during the motion of the vehicle and the payload along the IB. An external disturbance force is applied to the rod which constitutes the IB in order to test the robustness of the developed controllers. Investigations are carried out on the effect of changing the level and duration of the disturbance force, and changing the speed of the payload on the system during the balancing mode. Simulation results of both control algorithms are analyzed on a comparative basis.

Probability of Solar Flares Turn out to Form a Coronal Mass Ejections Events due to the Characterization of Solar Radio Burst Type II and III

Abstract: The solar flare and Coronal Mass Ejections (CMEs) are well known as one of the most massive eruptions which potentially create major disturbances in the interplanetary medium and initiate severe magnetic storms when they collide with the Earth’s magnetosphere. However, how far the solar flare can contribute to the formation of the CMEs is still not easy to be understood. These phenomena are associated with II and III burst it also divided by sub-type of burst depending on the physical characteristics and different mechanisms. In this work, we used a Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy in Transportable Observatories (CALLISTO) system. The aim of the present study is to reveal dynamical properties of solar burst type II and III due to several mechanisms. Most of the cases of both solar radio bursts can be found in the range less that 400 MHz. Based on solar flare monitoring within 24 hours, the CMEs that has the potential to explode will dominantly be a class of M1 solar flare. Overall, the tendencies of SRBT III burst form the solar radio burst type III at 187 MHz to 449 MHz. Based on solar observations, it is evident that the explosive, short time-scale energy release during flares and the long term, gradual energy release expressed by CMEs can be reasonably understood only if both processes are taken as common and probably not independent signatures of a destabilization of pre-existing coronal magnetic field structures. The configurations of several active regions can be sourced regions of CMEs formation. The study of the formation, acceleration and propagation of CMEs requires advanced and powerful observational tools in different spectral ranges as many ‘stages’ as possible between the photosphere of the Sun and magnetosphere of the Sun and magnetosphere of the Earth. In conclusion, this range is a current regime of solar radio bursts during CMEs events.